[1] Headed from 1885 onwards by Jacob H. Schiff, Loeb's son-in-law, it grew to be one of the most influential investment banks in the late-19th and early-20th centuries, financing America's expanding railways and growth companies, including Western Union and Westinghouse, and thereby becoming the principal rival of J.P. Morgan & Co.

However, the firm's fortunes began to fade following the end of World War II in 1945 - it failed to keep pace with a rapidly changing investment-banking industry, in which Kuhn, Loeb's old-world, genteel ways, did not seem[original research?]

Kuhn and Loeb had created a successful merchandising business in Cincinnati, Ohio, when they decided to move east, to New York, to take advantage of the country's burgeoning economic expansion.

Company records indicate that by the time Kuhn and Loeb established their partnership, they were able to capitalize it at $500,000 (equivalent of about $11.2 million in 2024).

Schiff was instrumental in the reorganization of the Union Pacific in 1897, helping to place the firm on sound financial footing.

In 1901, with Kuhn, Loeb's financial support, E. H. Harriman famously battled James Jerome Hill and J.P. Morgan to acquire control of the Northern Pacific Railroad.

Rockefeller invested in many syndicates with the bank, including major stakes in the prominent railroad companies, as well as contributing to its consolidation of the Chicago meatpackers, which resulted in the formation of a leading trust.

Overseas ventures that Rockefeller also got involved with included the bank's loans to the Chinese and Imperial Japanese governments.

The firm also joined a partnership with Rockefeller in 1911 to gain control of the Equitable Trust Company, which was later to merge and become the Chase Bank.

Later on, following World War II, their cousin Sigmund Warburg would briefly continue this relationship as a partner and Executive Director of the firm.

In 1993, under then newly appointed CEO, Harvey Golub, the firm sold its retail brokerage operations to Primerica.

Former Kuhn, Loeb employees remain in senior positions throughout Wall Street, and until recently, at Lehman Brothers.

Vestiges of the firm survived in the form of Lehman Brothers' extensive fixed income capabilities, including many of their bond indices, such as the Government/Credit index.